The conventional CPU cooling method of electronic products attaches the heatsink made of aluminum or copper to the heating element, whereby the heat diffuses from the bottom to the top by means of the contact transfer, and further utilizes the cooling fan to dissipate the heat. However, as a result of constantly upgrading performance of the CPU, the increasing speed of the heat accumulation has made the heating element demand go far beyond the bounds of the heat transfer speed of the cooling device.
Therefore, in Appendix 1, Taiwan Patent Publication No. M259218 “Phase Change Cooling Device”, there are a cylinder 10 and a plurality of fins 20 integrally formed on the cylinder 10. The cylinder 10 is formed an enclosed cavity 40 therein, where is filled with a working fluid capable of transforming between gas phase and liquid phase depending on the temperature variation, in an attempt to enhance the overall heat transfer efficiency of the cooling device by means of the working fluid with high thermal conductivity.
However, as the working fluid is still inside the cavity 40, when the heat gradually diffuses from bottom up, the fins 20 are in a non-isothermal phenomenon, which has a higher temperature over the top portion and a lower temperature over the bottom portion.
As such, in Appendix 2, Taiwan Patent Publication No. M584269 “Fins with perturbing liquid therein”, the base 30 of the fin 40 is disposed an enclosed chamber 31 therein, where is filled with a thermal conductive liquid 32, and a perturbing device 60 thereon. The perturbing device 60 is composed of a driving device 62 and a perturbing element 61, which the driving device 62 impels the perturbing element 61 to rotate so that the perturbing element 61 applies the turbulent flow effect to the thermal conductive liquid 32, securing a rapid and uniform diffusion of heat throughout the fin 41 and an upgrading cooling performance.
Notwithstanding, the perturbing element 61 in the aforementioned patent has the following two layout patterns:
First one, as shown in FIG. 5 of Appendix 2, has a driving device 62 disposed outside the chamber 31 and a shaft penetrating the chamber 31 from outside in for impelling the perturbing element 61 to rotate.
Such layout, due to an additional driving device 62 disposed outside the chamber 31, makes the overall size of the cooling device and production cost on the hike relatively. Besides, the driving device 62 utilizes a shaft, which penetrates in the chamber, to drive the perturbing element 61 and to form a gap between the shaft and the wall of the chamber 31. As a consequence, the chamber 31 is no longer an enclosed space. While the thermal conductive liquid 32 absorbs the heat of the heat source 80, the pressure inside the chamber 31 will rise, and the thermal conductive liquid 32 is apt to overflow therefrom.
Second one, as shown in FIG. 6 of Appendix 2, extends the rotor shaft of the cooling fan 50 and penetrates in a chamber 31 so as to drive a perturbing element 61 to rotate with it.
Although such layout reduces of the size of the cooling device and the production cost, the issue that the thermal conductive liquid 32 overflows due to the rising pressure inside the chamber 31 still exists. Besides, the perturbing element 61 and the cooling fan 50 synchronously rotate around the same shaft. However, the density of the thermal conductive liquid 32 is greater than air, and thus the resistance born on the perturbing element 61 is higher than that on the cooling fan 50. The resistance born on the perturbing element 61 will be transmitted to the cooling fan 50 via the rotation shaft, resulting in an unstable rotation speed of the cooling fan 50 and an impact on the cooling efficiency.